CN114057391A

CN114057391A - High-refraction glass

Info

Publication number: CN114057391A
Application number: CN202110871079.5A
Authority: CN
Inventors: B·施罗德; U·沃尔夫; S·汉森
Original assignee: Schott AG
Current assignee: Schott AG
Priority date: 2020-07-30
Filing date: 2021-07-30
Publication date: 2022-02-18
Also published as: US11958770B2; JP2022027700A; US20220033297A1; DE102020120171A1

Abstract

The invention relates to a high refractive index, in particular a refractive index higher than 2.0 over the entire visible range of the spectrum and/or a refractive index n_dIs at least 2.02 glass. Preferably, the glass has a high transmission in the visible wavelength range, in particular also in the shorter visible wavelength range. The invention also relates to a method for producing glass and to the use of glass. The glass according to the invention can be used in particular for AR glasses. Other uses are for example as lenses or waveguides in the optical field.

Description

High-refraction glass

Technical Field

The invention relates to a transparent optical element having a high refractive index, in particular a refractive index higher than 2.00 and/or a refractive index n in the entire visible range of the spectrum_dIs at least 2.02 glass. Preferably, the glass has a high transmission in the visible wavelength range, in particular also in the shorter visible wavelength range. The invention also relates to a method for producing glass and to the use of glass. The glass according to the invention can be used in particular for AR glasses. Other uses are for example as lenses or waveguides in the optical field.

Background

The so-called Augmented Reality (AR) field is becoming more and more important. This reason is thatThe solution is an augmentation of reality, particularly through computer-generated information that is visually presented. For this purpose, special glasses, so-called AR glasses, are usually used. To produce such lenses, glasses with particularly high refractive indices are required because they increase the field of view (FoV). Furthermore, the glass should preferably have a particularly good transmission in the visible wavelength range. In this connection, the transmission, in particular in the shorter visible wavelength range, for example in the blue range from 420nm to 490nm, in particular at 420nm or 460nm, has proven to be problematic in the case of particularly high-refractive glasses. In this connection, this phenomenon is also described as "UV edge" of the glass. When the UV edge shifts too far into the visible range or rises sharply short, the transmission performance in the shorter visible wavelength range is poor. Furthermore, it has been shown to be difficult to provide glasses having a particularly high refractive index over the entire visible range (in particular from 380nm to 750 nm). Thus, for example, the refractive index n is known_dA glass having a refractive index of 2.001 but not reaching at least 2.000 at other wavelengths in the visible range.

In the past, glasses made from the niobium phosphate system have been used, among others. However, these glasses are very problematic in production, since oxygen depletion, in particular due to the high melting and refining temperatures, leads to Nb in the reduced phosphate system in an oxidation state below V, resulting in a strong brown or even black coloration. Furthermore, this series of glasses not only tends to crystallize at the interface, like lanthanum borate or borosilicate systems, but also exhibits very fast crystal growth, which makes post-cooling (stress cooling or refractive power adjustment) critical for the optionally pre-nucleated glass. In addition, glass is relatively brittle and therefore difficult to polish into thin wafers.

Thus, in particular, a refractive index higher than 2.0 and/or a refractive index n over the entire visible range of the spectrum should be provided_dIs at least 2.02 glass. Preferably, the glass is characterized by excellent transmission properties, in particular also at shorter visible wavelength ranges, for example at 420nm and/or 460 nm. Furthermore, the batch costs should be kept moderate. The glass should be characterized by good manufacturing potential without ripples. In addition, the method can be used for producing a composite materialIt should be possible to produce wafers from glass with good yields. In particular, good hot glass forming and good processing of the glass should be possible. Despite the high refractive index, the glass should have as low a density as possible. Therefore, the wearing comfort of the AR eyeglasses can be improved in particular.

Disclosure of Invention

It is therefore an object of the present invention to provide a glass which overcomes the disadvantages of the prior art. This object is achieved by the subject matter of the claims.

In one aspect, the invention relates to a glass comprising the following ingredients in weight percent:

composition (I)	Portion (weight%)
		SiO₂	2-10
B₂O₃	2-10
		La₂O₃	40-55
Gd₂O₃	4-11
		Nb₂O₅	6-14
TiO₂	8-18.5
		ZrO₂	5-11

Wherein the refractive index n of the glass_dIs at least 2.02, wherein, La₂O₃、Nb₂O₅、TiO₂And ZrO₂Is at least 76.5 wt.%, and wherein La₂O₃、Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portions of (a) to (b) is at least 3.85: 1.

wherein the refractive index n of the glass_dIs at least 2.03, wherein, La₂O₃、Nb₂O₅、TiO₂And ZrO₂Is at least 76.5 wt.%, wherein La₂O₃、Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂And wherein the internal transmission TI of the glass, measured at a wavelength of 460nm and a sample thickness of 10mm, is at least 84% or at least 85%.

Preferably, the glass comprises the following constituents in weight-%:

composition (I)	Portion (weight%)
		SiO₂	4-9
B₂O₃	4-8
		La₂O₃	44-50
Gd₂O₃	4.5-9
		Nb₂O₅	8-12
TiO₂	9-17
		ZrO₂	6-8

Preferably, the glass comprises the following constituents in weight-%:

composition (I)	Portion (weight%)
		SiO₂	2-10
B₂O₃	2-10
		La₂O₃	40-55
Gd₂O₃	4.5-9
		Nb₂O₅	6-14
TiO₂	8-18.5
		ZrO₂	6-11

Preferably, the glass comprises the following constituents in weight-%:

preferably, the glass comprises the following constituents in weight-%:

composition (I)	Portion (weight%)
		SiO₂	2-10
B₂O₃	2-10
		La₂O₃	40-55
Gd₂O₃	4-11
		Nb₂O₅	6-14
TiO₂	8-18.5
		ZrO₂	5-11
BaO	1-8

Preferably, the glass comprises the following constituents in weight-%:

composition (I)	Portion (weight%)
		SiO₂	2-10
B₂O₃	2-10
		La₂O₃	40-55
Gd₂O₃	4-11
		Nb₂O₅	6-14
TiO₂	8-18.5
		ZrO₂	5-11
BaO	2-6

Preferably, the glass comprises the following constituents in weight-%:

in one aspect, the invention relates to a glass having a refractive index n_dIn the range of 2.02 to 2.08,Preferably 2.03 to 2.07, further preferably 2.04 to 2.06, the internal transmission TI is at least 85%, preferably at least 90%, further preferably at least 91%, further preferably at least 92%, further preferably at least 93%, further preferably at least 94%, further preferably at least 95%, further preferably at least 96%, further preferably at least 97%, wherein the internal transmission is measured at a wavelength of 460nm and a sample thickness of 10 mm.

In one aspect, the invention relates to a glass having a refractive index n_dIs at least 2.02, at least 2.03 or at least 2.04, and an internal transmission TI of at least 85%, preferably at least 90%, further preferably at least 91%, further preferably at least 92%, further preferably at least 93%, further preferably at least 94%, further preferably at least 95%, further preferably at least 96%, further preferably at least 97%, wherein the internal transmission is measured at a wavelength of 460nm and a sample thickness of 10 mm.

The internal transmission and the internal transmission factor, respectively, can be measured in a manner known to the person skilled in the art, for example according to DIN 5036-1: 1978. in the present specification, the data given in relation to internal transmission relate to a 10mm sample thickness. Reference to "sample thickness" does not mean that the glass has this thickness, but only that the data given in relation to internal transmission relate to this thickness.

Unless otherwise stated or apparent to one skilled in the art, the measurements described herein were performed at 20 ℃ and 101.3kPa gas pressure.

Refractive index n of glass of the present invention_dIs at least 2.02. Preferably, the refractive index n_dIn the range of 2.02 to 2.08, preferably 2.03 to 2.07, further preferably 2.04 to 2.06. Refractive index n_dKnown to those skilled in the art and which in particular has a refractive index at a wavelength of about 587.6nm (the wavelength of the d-line of helium). The person skilled in the art knows how to determine the refractive index n_d. The glasses according to the invention may, for example, have a refractive index n of at least 2.02, at least 2.03 or at least 2.04_d. The glass of the invention may, for example, have a fold of at most 2.08, at most 2.07 or at most 2.06Index of refraction n_d。

The refractive index is preferably determined by means of a refractometer, in particular a V-cube (block) refractometer. Here, in particular, a sample having a square or approximately square base (for example, about 20mm × 20mm × 5mm in size) may be used. When measured by a V-cube refractometer, the sample is typically placed in a V-cube prism having a known refractive index. The refraction of the incident beam depends on the difference between the refractive index of the sample and the refractive index of the V-cube prism, so that the refractive index of the sample can be determined. Preferably, the measurement is performed at a temperature of 22 ℃.

The refractive index depends on the wavelength of the light and can be determined at different wavelengths, e.g. n_dAt about 587.6nm, nF at about 486nm and nC at about 656 nm. Preferably, the glass has a refractive index higher than 2.00, further preferably higher than 2.01, in the entire visible range of the spectrum (in particular 380nm to 750 nm). Preferably, the glass has a refractive index in the range of 2.00 to 2.10, for example 2.01 to 2.09, 2.02 to 2.08, 2.03 to 2.07 or 2.04 to 2.06, throughout the visible range of the spectrum. The refractive index of the glass over the entire visible range of the spectrum may be, for example, at least 2.00, at least 2.01, at least 2.02, at least 2.03, or at least 2.04. The glass may have a refractive index across the visible range of the spectrum of, for example, at most 2.10, at most 2.09, at most 2.08, at most 2.07, or at most 2.06.

The refractive index nF is the refractive index at a wavelength of about 486 nm. The glass of the invention preferably has a refractive index nF in the range from 2.00 to 2.10, for example from 2.01 to 2.09, from 2.02 to 2.08, from 2.03 to 2.07 or from 2.04 to 2.06. The refractive index nF may, for example, be at least 2.00, at least 2.01, at least 2.02, at least 2.03, or at least 2.04. The refractive index nF may, for example, be at most 2.10, at most 2.09, at most 2.08, at most 2.07 or at most 2.06.

The refractive index nC is the refractive index at a wavelength of about 656 nm. The refractive index nC of the glass of the invention is preferably in the range from 2.00 to 2.06, for example from 2.01 to 2.05 or from 2.02 to 2.04. The refractive index nC may for example be at least 2.00, at least 2.01 or at least 2.02. The refractive index nC may for example be at most 2.06, at most 2.05 or at most 2.04.

Preferably, the glass has a thickness of 20.0 to 35.0. In particular a dispersion v of 22.5 to 32.5 or 25.0 to 30.0_d. Dispersion v_dMay for example be at least 20.0, at least 22.5 or at least 25.0. Dispersion v_dMay for example be at most 35.0, at most 32.5 or at most 30.0.

The density of the glass according to the invention is preferably 4.90g/cm³To 5.50g/cm³Further preferably 4.95g/cm³To 5.40g/cm³Further preferably 5.00g/cm³To 5.35g/cm³The range of (1). The density may, for example, be at least 4.90g/cm³At least 4.95g/cm³Or at least 5.00g/cm³. The density may, for example, be at most 5.50g/cm³At most 5.40g/cm³Or up to 5.35g/cm³. In some embodiments, the density of the glass is less than 5.30g/cm³Preferably less than 5.25g/cm³Preferably less than 5.20g/cm³Preferably less than 5.15g/cm³。

It is well known that the density of glass increases with increasing refractive index. Preferably, however, the glass according to the invention is also characterized in particular in that, despite the high refractive index, the density is relatively low. Density and refractive index n_dThe ratio of (A) to (B) is preferably in the range of 2.30 to 2.80g/cm³Further preferably 2.35 to 2.75g/cm³Further preferably 2.40 to 2.70g/cm³Further preferably 2.45 to 2.65g/cm³Further preferably 2.50 to 2.60g/cm³The range of (1). Density and refractive index n_dThe ratio of the density is determined by the value of the density (g/cm)³) Divided by refractive index n_dIs determined. Particularly preferably, the density and the refractive index n_dThe ratio of the ratio is less than 2.80g/cm³Further preferably less than 2.75g/cm³Further preferably less than 2.70g/cm³Further preferably less than 2.65g/cm³Further preferably less than 2.60g/cm³Further preferably less than 2.55g/cm³。

Preferably, the glass according to the invention has a high transmission in the visible range, in particular also in the shorter visible wavelength range, for example at 420nm and/or 460 nm. Thus, preferably, the UV edge can be found at relatively short wavelengths, despite the high refractive properties.

Preferably, the internal transmission TI of the glass is at least 25%, further preferably at least 30%, further preferably at least 40%, further preferably at least 50%, further preferably at least 60%, further preferably at least 70%, further preferably at least 75%, further preferably at least 80%, further preferably at least 85%, further preferably at least 87.5%, further preferably at least 90%, measured at a wavelength of 420nm and a sample thickness of 10 mm. In some embodiments, the glass has an internal transmission TI of at most 99%, at most 98%, at most 95%, or at most 92.5%, measured at a wavelength of 420nm and a sample thickness of 10 mm.

Preferably, the internal transmission TI of the glass is at least 63%, further preferably at least 65%, further preferably at least 70%, further preferably at least 75%, further preferably at least 80%, further preferably at least 85%, further preferably at least 87.5%, further preferably at least 90%, further preferably at least 91%, further preferably at least 92%, further preferably at least 93%, further preferably at least 94%, further preferably at least 95%, further preferably at least 96%, further preferably at least 97%, measured at a wavelength of 460nm and a sample thickness of 10 mm. In some embodiments, the glass has an internal transmission TI of at most 99.99%, at most 99.9%, at most 99%, or at most 98%, measured at a wavelength of 460nm and a sample thickness of 10 mm.

When T is_gAt very high, the aftercooling lasts longer. However, T_gIs also a measure of chemical stability and hardness (T)_gThe higher the network, the more stable the network and therefore the harder the glass and the stronger the chemical resistance). Chemical resistance is inherently good, but hardness is too high and expensive because grinding and polishing lasts longer and must be performed more carefully so that not too many microcracks develop during this period. It is therefore preferred that the glass transition temperature T of the glasses according to the invention_gIn the range of 700 ℃ to 800 ℃, further preferably 710 ℃ to 780 ℃, further preferably 720 ℃ to 760 ℃, further preferably 730 ℃ to 750 ℃. GlassTransition temperature T_gMay for example be at least 700 ℃, at least 710 ℃, at least 720 ℃ or at least 730 ℃. Glass transition temperature T_gMay for example be at most 800 ℃, at most 780 ℃, at most 760 ℃ or at most 750 ℃.

Viscosity of 10¹The temperature T1 at dPas is preferably in the range 1100 ℃ to 1250 ℃, further preferably 1150 ℃ to 1200 ℃. Thus, the glass composition of the present invention allows for a particularly low melting temperature. The temperature T1 may, for example, be at least 1100 ℃ or at least 1150 ℃. The temperature T1 may, for example, be at most 1250 ℃ or at most 1200 ℃.

Viscosity of 10⁴The temperature T4 at dPas is preferably in the range 875 ℃ to 1025 ℃, more preferably 925 ℃ to 975 ℃. The temperature T4 may, for example, be at least 875 ℃ or at least 925 ℃. The temperature T4 may, for example, be at most 1025 ℃ or at most 975 ℃.

Viscosity of 10^7.6The softening temperature T7.6 at dPas is preferably in the range 750 ℃ to 900 ℃, further preferably 800 ℃ to 850 ℃. The softening temperature T7.6 may, for example, be at least 750 ℃ or at least 800 ℃. The softening temperature T7.6 may, for example, be at most 900 ℃ or at most 850 ℃.

The crystallization temperature TK is preferably in the range of 1000 ℃ to 1200 ℃, further preferably 1025 ℃ to 1175 ℃, further preferably 1050 ℃ to 1150 ℃. The viscosity at TK is preferably in the range of 10 to 100 dPas. The crystallization temperature TK may be, for example, at least 1000 ℃, at least 1025 ℃ or at least 1050 ℃. The crystallization temperature TK may, for example, be at most 1200 ℃, at most 1175 ℃ or at most 1150 ℃.

The viscosity of the glass can be determined by means of a rotational viscometer, for example, according to DIN ISO 7884-2: 1998-2. The dependence of the viscosity on temperature can be determined by using a VFT curve (Vogel-Fulcher-Tammann equation). The softening temperature can be determined by means of a fiber elongation viscometer according to ISO 7884-2.

Preferably, the glass of the invention has a Coefficient of Thermal Expansion (CTE) (CTE (20, 300)) in the range of 6.7 to 10.0ppm/K, further preferably 7.0 to 9.7ppm/K, further preferably 7.3 to 9.4ppm/K, further preferably 7.6 to 9.1ppm/K, further preferably 7.9 to 8.8ppm/K, further preferably 8.0 to 8.7ppm/K, further preferably 8.1 to 8.6ppm/K at a temperature range of 20 ℃ to 300 ℃. The CTE should be well in line with the coating, wherein in particular very high CTE values often lead to problems, since in this range the polymers are often not characterized by a linear CTE curve, but by a steeper curve. Furthermore, when the glass has an unsuitable CTE, it is possible that cracks form or the layer spalls. For these reasons, the above CTE values are particularly preferred. The CTE may be, for example, at least 6.7ppm/K, at least 7.0ppm/K, at least 7.3ppm/K, at least 7.6ppm/K, at least 7.9ppm/K, at least 8.0ppm/K, or at least 8.1 ppm/K. The CTE may be, for example, at most 10.0ppm/K, at most 9.7ppm/K, at most 9.4ppm/K, at most 9.1ppm/K, at most 8.8ppm/K, at most 8.7ppm/K, or at most 8.6 ppm/K.

The glass according to the invention contains SiO in a proportion of 2 to 10 wt.%, preferably 4 to 9 wt.%₂。SiO₂Is a glass former. The oxide greatly improves chemical resistance but also increases processing temperature. When it is used in a very high amount, the refractive index according to the present invention cannot be achieved. Particularly preferably, SiO₂The fraction of (b) is in the range of 4.5 to 7 wt.%, further preferably 4.75 to 6.5 wt.%, further preferably 5 to 6 wt.%. SiO 2₂The fraction of (c) may be, for example, at least 2 wt.%, at least 4 wt.%, at least 4.5 wt.%, at least 4.75 wt.%, or at least 5 wt.%. SiO 2₂The fraction of (c) may be, for example, at most 10 wt.%, at most 9 wt.%, at most 7 wt.%, at most 6.5 wt.%, or at most 6 wt.%.

Has proven that B₂O₃Particularly suitable for achieving low melting temperatures. However, especially due to its corrosive nature towards the molten pot material, B₂O₃Is limited in content. The glass of the present invention comprises 2 to 10 wt.%, preferably 3 to 9 wt.%, further preferably 4 to 8.5 wt.%, further preferably 5 to 8 wt.%, further preferably 5.25 to 6.5 wt.% of B₂O₃。B₂O₃The fraction of (c) may be, for example, at least 2 wt.%, at least 3 wt.%, at least 4 wt.%, at least 5 wt.%, or at least 5.25 wt.%. B is₂O₃In proportion ofMay for example be at most 10 wt%, at most 9 wt%, at most 8.5 wt%, at most 8 wt% or at most 6.5 wt%.

When SiO is present₂And B₂O₃When the sum of the weight fractions of (a) is very high, this will negatively influence the refractive index. On the other hand, SiO is required₂And B₂O₃As network formers, the proportions should also not be too low. SiO 2₂And B₂O₃The sum of the weight fractions of (a) is preferably 6 to 16 wt.%, further preferably 7 to 15 wt.%, further preferably 8 to 14 wt.%, further preferably 9 to 13 wt.%. SiO 2₂And B₂O₃The sum of the weight fractions of (b) may be, for example, at least 6 wt.%, at least 7 wt.%, at least 8 wt.%, or at least 9 wt.%. SiO 2₂And B₂O₃The sum of the weight fractions of (b) may be, for example, at most 16 wt.%, at most 15 wt.%, at most 14 wt.% or at most 13 wt.%.

In some embodiments, the SiO₂In a weight fraction higher than B₂O₃Due to the weight ratio of with B₂O₃In contrast, SiO₂Does not corrode the refractory material. However, B₂O₃Is more advantageous for the melting behavior. Thus, preferably, SiO₂And B₂O₃In a comparable fraction. SiO 2₂Fraction of (A) and B₂O₃The weight ratio of the portions of (a) is preferably in the range of 0.45:1 to 1.45:1, further preferably 0.55:1 to 1.35:1, further preferably 0.65:1 to 1.25: 1. In a particularly preferred embodiment, B₂O₃Has a ratio of at least SiO₂The fraction of (c) is equally high. SiO 2₂Fraction of (A) and B₂O₃The weight ratio of the fractions of (a) can be advantageously used to suitably adjust the melting temperature and the corrosiveness of the melt. SiO 2₂Fraction of (A) and B₂O₃The weight ratio of the fractions of (b) may be, for example, at least 0.45:1, at least 0.55:1 or at least 0.65: 1. SiO 2₂Fraction of (A) and B₂O₃The weight ratio of the fractions of (b) may be, for example, at most 1.45:1, at most 1.35:1 or at most 1.25: 1. In some embodiments, the SiO₂Part (b) ofThe sum of the forehead and B₂O₃The ratio of the fractions of (b) is at least 1:1 or higher than 1:1, for example at least 1.01:1, at least 1.02:1, at least 1.03:1 or at least 1.04:1 by weight.

La in glass according to the invention₂O₃、Nb₂O₅、TiO₂And ZrO₂The sum of the fractions of (A) is at least 76.5% by weight. Preferably, La₂O₃、Nb₂O₅、TiO₂And ZrO₂The sum of the fractions of (a) is in the range of 76.5 to 85 wt.%, further preferably 77 to 84 wt.%, further preferably 78 to 83 wt.%, further preferably 79 to 82.5 wt.%. Particularly preferably, La is present in the glass according to the invention₂O₃、Nb₂O₅、TiO₂And ZrO₂Even at least 80% by weight. A high proportion of these components is advantageous for achieving a particularly high refractive index. However, it is also possible for the tendency to crystallize to increase, so that it may be advantageous to limit the content. La₂O₃、Nb₂O₅、TiO₂And ZrO₂The sum of the fractions of (b) may be, for example, at least 76.5 wt.%, at least 77 wt.%, at least 78 wt.%, or at least 79 wt.%. La₂O₃、Nb₂O₅、TiO₂And ZrO₂The sum of the fractions of (b) may be, for example, at most 85% by weight, at most 84% by weight, at most 83% by weight or at most 82.5% by weight.

La₂O₃、Nb₂O₅、TiO₂And ZrO₂Sum of the fractions of (A) and SiO₂And B₂O₃The weight ratio of the sum of the fractions of (b) is preferably in the range of 6.25:1 to 8.35:1, further preferably 6.75:1 to 7.85:1, further preferably 6.95:1 to 7.65:1, further preferably 7.05:1 to 7.55:1, further preferably 7.15:1 to 7.45: 1. La₂O₃、Nb₂O₅、TiO₂And ZrO₂Sum of the fractions of (A) and SiO₂And B₂O₃The weight ratio of the sum of the fractions of (b) may be, for example, at least 6.25:1, at least 6.75:1, at least 6.95:1, at least 7.05:1 or at least 7.15:1。La₂O₃、Nb₂O₅、TiO₂And ZrO₂Sum of the fractions of (A) and SiO₂And B₂O₃The weight ratio of the sum of the fractions of (b) may, for example, be at most 8.35:1, at most 7.85:1, at most 7.65:1, at most 7.55:1 or at most 7.45: 1.

One of the main components of the glass according to the invention is La₂O₃The proportion is from 40 to 55% by weight. La₂O₃With SiO₂And B₂O₃Together forming a dense glass network, TiO₂Embedded therein. La₂O₃Is stable and not sensitive to oxidation-reduction and is also more expensive and available than Gd₂O₃And Nb₂O₅Is more advantageous. Preferably, La₂O₃The proportion of (b) is in the range of 44 to 50% by weight, further preferably 45 to 49% by weight. When La₂O₃When the fraction of (b) is increased unfavorably with respect to the other high refractive component, then this has a negative effect on the refractive index. Furthermore, in La₂O₃The tendency to crystallize also increases in the case of very high fractions of (b). La₂O₃The fraction of (c) may be, for example, at least 40 wt.%, at least 44 wt.%, or at least 45 wt.%. La₂O₃The fraction of (c) may be, for example, at most 55 wt.%, at most 50 wt.%, or at most 49 wt.%.

Preferably, the SiO of the glass of the invention₂And B₂O₃Sum of the fractions of (A) and La₂O₃The weight ratio of the portions of (a) is in the range of 0.10:1 to 0.40:1, further preferably 0.15:1 to 0.35:1, further preferably 0.16:1 to 0.32:1, further preferably 0.18:1 to 0.28:1, further preferably 0.20:1 to 0.26:1, further preferably 0.21:1 to 0.25: 1. SiO 2₂And B₂O₃Sum of the fractions of (A) and La₂O₃The weight ratio of the fractions of (b) may be, for example, at least 0.10:1, at least 0.15:1, at least 0.16:1, at least 0.18:1, at least 0.20:1 or at least 0.21: 1. SiO 2₂And B₂O₃Sum of the fractions of (A) and La₂O₃The weight ratio of the fractions of (b) may, for example, be at most 0.40:1. at most 0.35:1, at most 0.32:1, at most 0.28:1, at most 0.26:1, or at most 0.25: 1.

Nb, in addition to having a large influence on the refractive index₂O₅But also has a positive effect on the glass density. The density can be reduced by this component. It exhibits oxygen depletion and a tendency to form lower oxidation states, thus leading to more intense coloration. The glass of the present invention comprises 6 to 14 wt.%, preferably 8 to 12 wt.%, further preferably 10 to 12 wt.% of Nb₂O₅。Nb₂O₅The proportion of (b) may be, for example, at least 6 wt.%, at least 8 wt.%, or at least 10 wt.%. Nb₂O₅The fraction of (b) may be, for example, at most 14% by weight, at most 13% by weight or at most 12% by weight.

La₂O₃And Nb₂O₅The sum of the fractions of (a) is preferably in the range from 48 to 67% by weight, further preferably from 50 to 65% by weight, further preferably from 52.5 to 62.5% by weight, further preferably from 55 to 60% by weight. Preferably, La₂O₃And Nb₂O₅The sum of the fractions of (b) is at least 48 wt.%, at least 50 wt.%, at least 52.5 wt.%, at least 55 wt.% or particularly preferably at least 57.5 wt.%. La₂O₃And Nb₂O₅The sum of the fractions of (b) may be, for example, at most 67 wt.%, at most 65 wt.%, at most 62.5 wt.% or at most 60 wt.%.

The glass of the invention comprises 8 to 18.5 wt.%, preferably 9 to 18 wt.%, further preferably 12 to 17 wt.%, further preferably 14.5 to 16.5 wt.% of TiO₂。TiO₂It contributes significantly to a high refractive index and it also helps to keep the density relatively low. But limit the TiO₂The portion of (a) is advantageous because it may contribute to crystal growth as a nucleating agent, complicating thermal post-treatment, e.g. pressing. In some embodiments, the TiO₂Is at most 18.5 wt.%, at most 18 wt.%, at most 17 wt.%, or at most 16.5 wt.%. TiO2₂The fraction of (b) may be, for example, at least 8 wt.%, at least 9 wt.%, at least 12 wt.%, or at least 14.5 wt.%.

With TiO₂In contrast, ZrO₂Without exhibiting any tendency to form a lower colored oxidation state. However, its melting property and ZrO₂The rate of melting is limited. Higher ZrO₂The fraction of (c) is disadvantageous because a higher temperature is required for complete melting, which in turn has a negative effect on the transmission. Furthermore, ZrO₂Is not very pure (especially containing Fe impurities). Thus, ZrO₂The upper limit of the content is limited. ZrO in glass according to the invention₂The proportion of (b) is 5 to 11% by weight, preferably 6 to 8% by weight, further preferably 6.25 to 7.5% by weight. ZrO (ZrO)₂The limitation of the fraction of (a) is also advantageous in limiting potential crystal growth. In some embodiments, ZrO₂The fraction of (b) is at least 5 wt.%, at least 55 wt.%, at least 6 wt.%, at least 6.25 wt.%, or at least 6.5 wt.%. ZrO (ZrO)₂The fraction of (b) may be, for example, at most 11 wt.%, at most 8 wt.%, at most 7.5 wt.%, at most 7 wt.%, or at most 6.75 wt.%.

TiO₂And ZrO₂A significant contribution to the high refractive index, in particular TiO₂But also to a relatively low density. On the other hand, however, TiO₂And ZrO₂Should not be too high, especially in view of meltability, nucleation and crystallization. TiO2₂And ZrO₂The sum of the fractions of (a) is preferably in the range from 15 to 30% by weight, more preferably from 17.5 to 27.5% by weight, more preferably from 20 to 25% by weight. In some embodiments, the TiO₂And ZrO₂The sum of the fractions of (a) is at least 15 wt.%, at least 17.5 wt.%, at least 20 wt.%, at least 21 wt.%, at least 22 wt.%, or even at least 22.7 wt.%. TiO2₂And ZrO₂The sum of the fractions of (b) may be, for example, up to 30% by weight, up to 27.5% by weight or up to 25% by weight.

TiO in glasses due to tendency to crystallize₂The possible share is limited. Furthermore, TiO₂There is absorption in the blue wavelength range, even with ti (iv), while nb (v) absorbs in the UV. But with reduced TiO₂In contrast, reduced Nb₂O₅Resulting in significantly more absorption in the visible range. In contrast, La₂O₃Is stable and not redox sensitive. Accordingly, on the one hand, it is advantageous to limit the TiO content₂So that the UV absorption of the glass does not shift too much into the visible range in the case of fully oxidized components, but, on the other hand, with TiO₂For high n_dAnd low density contribution. La₂O₃And Nb₂O₅Also contribute to a high refractive index, they stabilize the network and remain-as long as they maintain the oxidation-UV transmittance in a larger range. Accordingly, it has proven advantageous to adjust ZrO in a targeted manner₂、La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the components (a) to (b) limits, in particular, the lower limit thereof. La of glass of the present invention₂O₃、Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portions of (a) to (b) is at least 3.85: 1. Preferably, La₂O₃、Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the fractions of (b) is in the range of 3.85:1 to 5.25:1, further preferably 3.90:1 to 5.00:1, further preferably 3.95:1 to 4.75:1, for example 3.96:1 to 4.50:1, 3.97:1 to 4.40:1, 3.98:1 to 4.35:1 or 3.99:1 to 4.30: 1. In some embodiments, La₂O₃、Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The ratio of the fractions of (a) is at least 3.85:1, at least 3.90:1, at least 3.95:1, at least 3.96:1, at least 3.97:1, at least 3.98:1, at least 3.99:1 or at least 4.00:1 by weight. La₂O₃、Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portions of (b) may be, for example, at most 5.25:1, at most 5.00:1, at most 4.75:1, at most 4.50:1, at most 4.40:1, at most 4.35:1, at most 4.30:1, at most 4.25:1, at most 4.20:1 or at most 4.15: 1.

Preferably, La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂In a weight ratio of at least 3.15:1, at least 3.25:1,At least 3.35:1, at least 3.46:1, particularly preferably at least 3.50:1, at least 3.56:1 or at least 3.60: 1. Preferably, La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the fractions of (a) is in the range of 3.15:1 to 4.25:1, further preferably 3.25:1 to 4.15:1, further preferably 3.35:1 to 4.05:1, further preferably 3.46:1 to 3.94:1, further preferably 3.50:1 to 3.90:1, further preferably 3.56:1 to 3.84:1, further preferably 3.60:1 to 3.80: 1. La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the fractions of (b) may be, for example, at most 4.25:1, at most 4.15:1, at most 4.05:1, at most 3.94:1, at most 3.90:1, at most 3.84:1 or at most 3.80: 1.

From the above regarding the color, n_dConsideration of the contribution, the density contribution and the crystallization, it is also advantageous to adjust the TiO in a targeted manner₂And Nb₂O₅The ratio of the fractions of (c). It is therefore particularly possible to select compositions so stable that they are only increased/decreased by SiO₂The range of refractive power can be variably adjusted. TiO2₂Fraction of (2) and Nb₂O₅The weight ratio of the portions of (a) is preferably in the range of 1.05:1 to 1.75:1, further preferably 1.15:1 to 1.65:1, further preferably 1.25:1 to 1.55: 1. TiO2₂Fraction of (2) and Nb₂O₅The weight ratio of the fractions of (b) may be, for example, at least 1.05:1, at least 1.15:1 or at least 1.25: 1. TiO2₂Fraction of (2) and Nb₂O₅The weight ratio of the fractions of (b) may be, for example, at most 1.75:1, at most 1.65:1 or at most 1.55: 1.

Preferably, La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂And ZrO₂The weight ratio of the sum of the fractions of (a) is in the range of 2.15:1 to 3.05:1, further preferably 2.25:1 to 2.95:1, further preferably 2.35:1 to 2.85:1, further preferably 2.45:1 to 2.75:1, further preferably 2.55:1 to 2.65: 1. In particular, La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂And ZrO₂The weight ratio of the sum of the fractions of (A) is preferably at least 2.15:1, at least 2.25:1Further preferably at least 2.35:1, further preferably at least 2.45:1, further preferably at least 2.53:1, further preferably at least 2.55: 1. La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂And ZrO₂The weight ratio of the sum of the fractions of (b) may, for example, be at most 3.05:1, at most 2.95:1, at most 2.85:1, at most 2.75:1 or at most 2.65: 1.

Nb₂O₅And ZrO₂The sum of the fractions of (a) is preferably in the range from 12 to 24% by weight, further preferably from 14 to 22% by weight, further preferably from 16 to 20% by weight. In particular, it is advantageous to limit Nb₂O₅And ZrO₂Because of the particularly refractory component ZrO₂Higher proportion of Nb₂O₅High fractions of (c) can be particularly problematic. Because of Nb₂O₅Especially in the interfacial region, e.g. ZrO₂The seed crystal, therefore, with recompression, slumping or post cooling, very large crystals in the volume may grow in an uncontrolled manner and the cast product may even break. There is also the risk that during the dip and in the worst case cooling forms a thick crystalline layer which can only be removed with very high difficulty without cracks. Nb₂O₅And ZrO₂The sum of the fractions of (b) may be, for example, at least 12 wt.%, at least 14 wt.%, or at least 16 wt.%. Nb₂O₅And ZrO₂The sum of the fractions of (b) may be, for example, at most 24% by weight, at most 22% by weight or at most 20% by weight.

The glass composition of the present invention is therefore based on a balance of most different, partly opposite effects. When the proportion of non-colouring components is increased too much, the stability of the glass may be negatively influenced. Furthermore, preferably, TiO₂And Nb₂O₅The fraction of (a) is very high, wherein care must also be taken here due to the crystallization process. TiO2₂Cheaper and has a more positive effect on the refractive index, but is disadvantageous in terms of UV absorption. This therefore leads further to the sums and ratios described below, which lead to particular advantagesAnd (3) glass.

TiO₂And ZrO₂Sum of the fractions of (1) and Nb₂O₅And ZrO₂The weight ratio of the sum of the fractions of (b) is preferably in the range of 1.05:1 to 1.45:1, further preferably 1.10:1 to 1.40:1, further preferably 1.15:1 to 1.35:1, further preferably 1.20:1 to 1.30: 1. TiO2₂And ZrO₂Sum of the fractions of (1) and Nb₂O₅And ZrO₂The weight ratio of the sum of the fractions of (b) may be, for example, at least 1.05:1, at least 1.10:1, at least 1.15:1 or at least 1.20: 1. TiO2₂And ZrO₂Sum of the fractions of (1) and Nb₂O₅And ZrO₂The weight ratio of the sum of the fractions of (b) may, for example, be at most 1.45:1, at most 1.40:1, at most 1.35:1 or at most 1.30: 1.

Preferably, Nb₂O₅And ZrO₂Is higher than the sum of the weight portions of TiO₂The weight fraction of (a). Particularly preferably, Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portions of (a) is in the range of 1.05:1 to 1.25: 1. Preferably, Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the fractions of (b) is higher than 1.10:1, for example from 1.11:1 to 1.20: 1. Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the fractions of (b) may be, for example, at least 1.05:1, higher than 1.10:1 or at least 1.11: 1. Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the fractions of (b) may be, for example, at most 1.25:1 or at most 1.20: 1.

La₂O₃、Nb₂O₅And ZrO₂The sum of the fractions of (a) is preferably in the range from 55 to 75% by weight, further preferably from 57.5 to 72.5% by weight, further preferably from 60 to 70% by weight. In some embodiments, La₂O₃、Nb₂O₅And ZrO₂The sum of the fractions of (a) is at least 55 wt.%, at least 57.5 wt.%, at least 60 wt.%, or even at least 62.0 wt.%, or at least 64.0 wt.%. La₂O₃、Nb₂O₅And ZrO₂May for example be up to75% more, 72.5% or 70% more by weight.

Preferably, TiO₂With ZrO₂The weight ratio of the fractions of (b) is at most 3.00:1, further preferably at most 2.80:1, further preferably at most 2.65:1, such as at most 2.60:1, at most 2.55:1, at most 2.50:1, at most 2.45:1 or at most 2.40: 1. Preferably, TiO₂With ZrO₂The weight ratio of the fractions of (a) is in the range of 1.10:1 to 3.00:1, further preferably 1.30:1 to 2.80:1, further preferably 1.50:1 to 2.65:1, further preferably 1.70:1 to 2.60:1, further preferably 1.80:1 to 2.55:1, further preferably 1.90:1 to 2.50:1, for example 2.00:1 to 2.45:1 or 2.10:1 to 2.40: 1. TiO2₂With ZrO₂The weight ratio of the fractions of (b) may be, for example, at least 1.10:1, at least 1.30:1, at least 1.50:1, at least 1.70:1, at least 1.80:1 or at least 1.90:1, in particular at least 2.00:1, at least 2.10:1, at least 2.20:1 or at least 2.30: 1.

The glass of the invention comprises 4 to 11 wt.%, preferably 4.5 to 9 wt.%, further preferably 4.75 to 8.5 wt.%, for example 5 to 8 wt.% Gd₂O₃. Very high Gd₂O₃May negatively affect the stability of the glass. Gd (Gd)₂O₃The fraction of (c) may be, for example, at least 4 wt.%, at least 4.5 wt.%, at least 4.75 wt.%, or at least 5 wt.%. Gd (Gd)₂O₃The fraction of (c) may be, for example, at most 11 wt.%, at most 10.5 wt.%, at most 10 wt.%, at most 9.5 wt.%, at most 9 wt.%, at most 8.5 wt.%, at most 8 wt.%, at most 7.5 wt.%, at most 7 wt.%, at most 6.5 wt.%, or at most 6 wt.%.

The glasses of the invention may comprise Y₂O₃. Preferably, Y₂O₃The fraction of (b) is in the range of 0 to 5 wt.%, for example 0.1 to 2 wt.%, 0.2 to 1 wt.% or 0.4 to 0.8 wt.%. Some examples do not contain Y₂O₃. High Y₂O₃The proportion of (b) may have a negative influence on the stability of the glass. Some embodiments comprise at most 5 wt.%, at most 2 wt.%, at most 1 wt.%, at most 0.8 wt.%, or a combination thereofY in an amount of at most 0.7 wt.%, at most 0.6 wt.%, at most 0.5 wt.%, at most 0.2 wt.%, or at most 0.1 wt.%₂O₃。

The glass of the present invention may comprise BaO. On the one hand, BaO can stabilize high TiO₂On the other hand, however, it may have a negative influence on the refractive index. Preferably, the proportion of BaO is in the range from 0 to 10% by weight, for example from 1 to 8% by weight, from 2 to 6% by weight or from 3 to 5% by weight. Some examples contain no BaO. The proportion of BaO can be, for example, at least 0.5 wt.%, at least 1 wt.%, more than 1.0 wt.%, at least 1.1 wt.%, at least 1.2 wt.%, at least 1.3 wt.%, at least 1.4 wt.%, at least 1.5 wt.%, at least 1.6 wt.%, at least 1.7 wt.%, at least 1.8 wt.%, at least 1.9 wt.%, at least 2 wt.%, at least 2.1 wt.%, at least 2.2 wt.%, at least 2.3 wt.%, at least 2.4 wt.%, at least 2.5 wt.%, at least 2.6 wt.%, at least 2.7 wt.%, at least 2.8 wt.%, at least 2.9 wt.%, or at least 3 wt.%. The proportion of BaO can be, for example, at most 10% by weight, at most 8% by weight, at most 7% by weight, at most 6% by weight or at most 5% by weight.

TiO₂The weight ratio of the fraction of (b) to the fraction of BaO may be, for example, in the range of 1.0:1 to 25:1, 1.5:1 to 20:1, 2.0:1 to 15:1, 2.5:1 to 10:1, 3.0:1 to 7.5:1, 3.5:1 to 6.0:1 or 4.0:1 to 5.0: 1. TiO2₂The weight ratio of the fraction of (b) to the fraction of BaO may be, for example, at least 1.0:1, at least 1.5:1, at least 2.0:1, at least 2.5:1, at least 3.0:1, at least 3.5:1 or at least 4.0: 1. TiO2₂The weight ratio of the fraction of (b) to the fraction of BaO may be, for example, at most 25:1, at most 20:1, at most 15:1, at most 10:1, at most 7.5:1, at most 6.0:1 or at most 5.0: 1.

The glasses of the present invention may comprise HfO₂In particular for increasing the refractive index. Preferably, HfO₂The fraction of (b) is in the range of 0 to 1 wt.%, for example 0.1 to 0.5 wt.% or 0.15 to 0.25 wt.%. Low HfO₂The share of (c) does not generally cause problems. However, some embodiments do not contain HfO₂。HfO₂Can be, for example, up to 1% by weight, up to 0.5% by weight%, at most 0.25 wt.%, at most 0.2 wt.%, at most 0.15 wt.%, or at most 0.1 wt.%. HfO₂The proportion of (b) may be, for example, at least 0.05% by weight, at least 0.10% by weight or at least 0.15% by weight.

The glasses of the invention may comprise alkali metal oxides, in particular Li₂And O. Preferably, however, the glass is free of alkali metal oxides. Preferably, Li₂The proportion of O is in the range from 0 to 0.5% by weight, for example from 0.05 to 0.2% by weight. Well known Li₂O is corrosive to ceramic pot and crucible materials and, therefore, is not used or is used only in small amounts where possible. Preferably, the glass is Li-free₂O。Li₂The proportion of O may be, for example, at most 0.5% by weight, at most 0.2% by weight or at most 0.1% by weight.

In one embodiment, the glass consists of at least 95.0% by weight, in particular at least 98.0% by weight or at least 99.0% by weight, of SiO as a constituent₂、B₂O₃、La₂O₃、Gd₂O₃、Nb₂O₅、TiO₂And ZrO₂Consisting of or consisting of the component SiO₂、B₂O₃、La₂O₃、Gd₂O₃、Nb₂O₅、TiO₂、ZrO₂And BaO. In one embodiment, the glass consists essentially entirely of the composition SiO₂、B₂O₃、La₂O₃、Gd₂O₃、Nb₂O₅、TiO₂、ZrO₂And HfO₂Consisting of or consisting of the component SiO₂、B₂O₃、La₂O₃、Gd₂O₃、Nb₂O₅、TiO₂、ZrO₂And BaO.

Preferably, the glass of the present invention does not contain one or more components selected from MgO, CaO, SrO and ZnO. It is particularly preferred that the glass does not contain MgO, CaO, SrO and ZnO. These components reduce the refractive power and destabilize the glass. The same applies to Al₂O₃. Therefore, preferably, the glass does not contain Al₂O₃。

Preferably, the glass does not contain one or more components WO₃、Ta₂O₅And/or GeO₂. Particularly preferably, the glass does not contain WO₃、Ta₂O₅And/or GeO₂. When these components are present, the batch cost increases significantly.

The melt of the glass may be fined with conventional fining agents. However, since the glass can be melted in particular at temperatures below 1300 ℃ and because of its low viscosity, the fining process can also be carried out at considerably milder temperatures, in order to favor UV transmission, for example Sb can be reduced₂O₃、As₂O₃And/or SnO₂Is reduced (e.g., to<0.1 wt.%) or may be omitted (pure physical clarification). Sb₂O₃、As₂O₃And SnO₂Can be used as clarifying agent. They are used only in low amounts. Particularly arsenic and antimony, are controversial for health hazards. The glass can be clarified without the need for chemical fining agents. Optionally, the glass may comprise one or more of the following constituents having a fining effect in weight%:

Sb₂O₃	0.0 to 0.5
		As₂O₃	0.0 to 0.5
SnO₂	0.0 to 0.5

By SnO₂Relatively high temperatures are required for clarification. Thus, preferably, SnO is omitted₂. Preferably, the glasses of the present invention are free of SnO₂。

Sb has not been proved₂O₃Is very effective for fining, and the absorption of Sb in the glass may deteriorate the UV edge. Therefore, Sb is preferably omitted₂O₃. Preferably, the glasses of the invention are Sb-free₂O₃。

As may be omitted, especially due to health hazards₂O₃. Preferably, the glasses of the invention are As-free₂O₃。

In embodiments of the present invention, sulfate may be used as a fining agent. However, the sulfate raw material generally contains iron, which may cause deterioration in transmittance. Therefore, preferably, the sulphate feedstock is omitted. Preferably, the glass of the present invention is sulfate-free.

In addition, As₂O₃And sulfates do not contribute to N resistance₂Air bubbles. When N is present₂If bubbles are to be avoided, then, for example, a protective gas, particularly preferably CO, can be used₂Or an argon atmosphere to make N₂Not near the melt surface.

The glass according to the invention is preferably free of absorbing constituents, in particular free of constituents which absorb in the visible range. Particularly preferably, the glass according to the invention is free of Fe₂O₃。

Preferably, the glass is phosphate-free (P)₂O₅) Since it makes the melt reducing to a considerable extent, the oxygen demand of the melt is significantly increased.

Preferably, the glass is substantially free of one or more, particularly preferably all, components selected from the group consisting of lead, bismuth, cadmium, nickel, platinum, arsenic and antimony.

When in this specification it is mentioned that the glass contains no constituents or contains no constituents, this means that for the constituents at most it is allowed to be present as impurities in the glass. Meaning that it is not added in large quantities. According to the invention, insignificant amounts are amounts of less than 200ppm, preferably less than 100ppm, preferably less than 50ppm and most preferably less than 10ppm (m/m).

Preferably, the proportion of platinum is particularly low, since platinum significantly reduces the transmission of the glass. Preferably, the fraction of platinum is below 5ppm, further preferably below 3ppm, further preferably below 1ppm, further preferably below 50ppb, further preferably below 20ppb (m/m).

In one aspect, the invention relates to a glass article comprising or consisting of the glass. The glass article may have different forms. Optionally, the article has the form

Glass for spectacles, in particular wafer stacks,

a wafer, in particular having a maximum diameter of 5.0cm to 40.0cm,

a lens, in particular a spherical lens, a prism or an aspherical lens (asphere), and/or

-an optical waveguide, in particular a fiber or a plate.

In another aspect, the invention relates to the use of a glass or glass article described herein in AR eyewear, wafer level optics, optical wafer applications, or typical optics. Alternatively or additionally, the glass described herein or the glass article described herein may be used as a wafer, a lens, a spherical lens, or an optical waveguide.

The invention also relates to a method for producing a glass or glass product according to the invention. The method comprises the following steps:

-melting a glass raw material,

-optionally forming a glass article from the glass melt,

-cooling the glass.

Due to the glass composition according to the present invention, the melting of the glass raw material can be performed at a relatively low melting temperature. A relatively low melting temperature is advantageous because the oxygen content of the batch does not decrease too much by it, which could otherwise lead to brown coloration by niobium or stronger yellow coloration by reduced titanium. Preferably, the melting of the glass raw material is performed at a melting temperature of less than 1400 ℃, further preferably less than 1350 ℃, further preferably less than 1300 ℃.

The production process of the present invention may further comprise a clarification step. Preferably, the clearing temperature is also relatively low, in particular below 1550 ℃, further preferably below 1450 ℃, further preferably below 1400 ℃. Pure physical clarification is preferred, so no clarifying agent is added.

Preferably, O is omitted₂Bubbling and O₂And (4) passing. Due to the preferably low process temperature and the absence of added O₂The melt retains sufficient O₂To maintain the highest oxidation state required for the UV edge, e.g., Nb (V) or Ti (IV), without the addition of Pt into the glass.

The cooling of the glass is preferably carried out at a cooling rate of from 1K/h to 20K/h, further preferably from 1.15K/h to 15K/h, further preferably from 1.3K/h to 10K/h. A low cooling rate is particularly advantageous to reduce or avoid stress. The glass can be cooled, for example, at a cooling rate of at least 1K/h, at least 1.15K/h, or at least 1.3K/h. The glass may be cooled, for example, at a cooling rate of at most 20K/h, at most 15K/h or at most 10K/h.

Detailed Description

The exemplary compositions in the following table, expressed in weight%, were melted and their properties were examined. The glass was cooled at a cooling rate of 10K/h.

TABLE 1

TABLE 2

TABLE 3

Table 1 shows example glasses 3 to 6 and 9 according to the invention and comparative examples 1, 2, 7 and 8 not according to the invention. In the case of comparative examples 1, 2 and 8, the component La₂O₃、Nb₂O₅、TiO₂And ZrO₂The sum of the fractions of (c) is low. These comparative examples have a low refractive index. In the case of comparative example 7, ZrO₂、La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portion of (b) is low. Comparative example 7 has relatively low internal transmittance at 420nm and 460 nm.

Table 2 shows example glasses 10 and 12 and 15 to 17 according to the present invention. Glasses 13 and 14 are comparative examples not according to the invention, with a low composition La₂O₃、Nb₂O₅、TiO₂、ZrO₂The sum of the fractions of (a) and a low refractive index. In the case of comparative example 11, ZrO₂、La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portion of (b) is low.

Table 3 shows example glasses 18 to 23 and 25 and 26 according to the present invention. Glass 24 is a comparative example not according to the invention, with a low composition La₂O₃、Nb₂O₅、TiO₂、ZrO₂The sum of the fractions of (a) and a low refractive index. In the case of comparative example 24, ZrO₂、La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portion of (b) is also low.

Glass transition temperatures T of glasses shown in tables 1 to 3_gIn the range of 724 ℃ to 754 ℃.

Other characteristic glass properties are shown in table 4 below, exemplarily by the glasses 7 to 9 and 11 described above.

TABLE 4

Other example glass compositions (wt%) and properties are shown in table 5.

Claims

1. A glass comprising the following ingredients in weight%:

Wherein the refractive index n of the glass_dIs at least 2.02, wherein, La₂O₃、Nb₂O₅、TiO₂And ZrO₂Is at least 76.5 wt.%, wherein La₂O₃、Nb₂O₅And ZrO₂Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portions of (A) is at least 3.85: 1.

2. The glass of claim 1, wherein Y is₂O₃In an amount of 0 to 5% by weight, in an amount of 0 to 10% by weight BaO and/or HfO₂The portion of (A) is 0 to 1% by weight.

3. Glass according to any of the preceding claims, wherein La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂And ZrO₂The weight ratio of the sum of the fractions of (A) is at least 2.25: 1.

4. Glass according to any preceding claim, wherein Nb₂O₅And ZrO₂Is higher than the sum of the weight portions of TiO₂The weight fraction of (a).

5. Glass according to any of the preceding claims, wherein La₂O₃And Nb₂O₅Sum of the fractions of (A) and (B) and TiO₂The weight ratio of the portions of (A) is at least 3.15: 1.

6. Glass according to any of the preceding claims, wherein La₂O₃、Nb₂O₅And ZrO₂The sum of the fractions of (a) is in the range of 55 to 75% by weight.

7. Glass according to any of the preceding claims, wherein the proportion of TiO2 is related to ZrO₂The weight ratio of the fractions of (b) is at most 3.00: 1.

8. glass according to any of the preceding claims, wherein Sb₂O₃The fraction of (B) is at most 50 ppm.

9. The glass of any one of the preceding claims, wherein the glass has an internal transmission TI of at least 80% as measured at a wavelength of 460nm and a sample thickness of 10 mm.

10. Glass according to any of the preceding claims, wherein Gd₂O₃Has a content of at most 9 wt.% of ZrO₂The proportion of (B) is at least 6% by weight.

11. Glass according to any of the preceding claims, wherein Gd₂O₃In the range of 4.5 to 9% by weight and ZrO₂The proportion of (B) is in the range from 6 to 11% by weight.

12. Glass according to any one of the preceding claims, wherein the share of BaO is in the range of 1 to 8 wt.%.

13. Glass according to any of the preceding claims, wherein the refractive index n of the glass is measured at a wavelength of 460nm and a sample thickness of 10mm_dIs at least 2.03 and the internal transmission TI is at least 85%.

14. Glass according to any of the preceding claims, wherein SiO₂Fraction of (A) and B₂O₃The weight ratio of the portions of (A) is at least 1: 1.

15. Glass according to any of the preceding claims, wherein La₂O₃、Nb₂O₅、TiO₂And ZrO₂Sum of the fractions of (A) and SiO₂And B₂O₃The weight ratio of the sum of the fractions of (a) is at least 7.15: 1.

16. Glass according to any of the preceding claims, wherein SiO₂And B₂O₃Sum of the fractions of (A) and La₂O₃The weight ratio of the portions of (a) is in the range of 0.15:1 to 0.35: 1.

17. The glass of any of the preceding claims, wherein TiO₂The weight ratio of the fraction of (b) to the fraction of BaO is in the range of 1.0:1 to 25: 1.

18. A glass article comprising the glass of any of the preceding claims in the form of

Glass for spectacles, in particular wafer stacks,

a wafer, in particular having a maximum diameter of 5.0cm to 40.0cm,

a lens, in particular a spherical lens, a prism or an aspherical lens, and/or

-an optical waveguide, in particular a fiber or a plate.

19. A method for producing a glass or glass article according to any of the preceding claims, comprising the steps of:

-melting a glass raw material,

-optionally forming a glass article from the glass melt,

-cooling the glass.

20. Use of a glass according to any one of claims 1 to 17 or a glass article according to claim 18 in AR glasses, wafer level optics, optical wafer applications or typical optics;

and/or as a wafer, lens, spherical lens, or optical waveguide.